Certain non-digestible polysaccharides, which are often termed prebiotic fibres, are fermented by micro-organisms in the gastrointestinal tract. Examples of these polysaccharides are inulin and its hydrolysis products. The products of the fermentation lead to the provision of energy, the selective stimulation of growth of lactic acid bacteria and the regulation of cellular metabolism. One class of these fermentation products are the short chain fatty acids acetate, propionate and butyrate.
Of the short chain fatty acids, propionate is thought to (i) mediate the reduced hepatic gluconeogenesis induced by non-digestible polysaccharides, (ii) inhibit gluconeogenesis in the liver, (iii) enhance glycolysis, (iv) lower plasma fatty acid concentrations, (v) inhibit ureagenesis in the liver, and (v) increase insulin sensitivity (Roberfroid et al; 1998; Annu. Rev. Nutr.; 18:117–43). Acetate, however, increases plasma fatty acid concentrations (Roberfroid et al; 1998; Annu. Rev. Nutr.; 18:117–43).
The selective production of propionate in the gastrointestinal tract would therefore be of benefit in the nutritional management of many conditions. However, the primary fatty acid which is produced upon fermentation of known non-digestible polysaccharides is acetate, followed by butyrate and propionate. Hence these non-digestible polysaccharides are not suitable for selectively increasing the production of propionate in the gastrointestinal tract.
Therefore, it is an object of this invention to provide a method for selectively increasing the production of propionate in the gastro-intestinal tract.